1. Field of the Invention
The invention pertains to a rotary catch lock of the general type indicated in the following. After being rotated into its end position, that is, its closed position, the rotary catch accepts a closing element; this closed position is maintained by a spring-loaded, pivoting latch. In this situation, the latch is in its locking position. When the latch is moved into a release position to release the rotary catch, the rotary catch can then be moved by a restoring force back into its other rotational end position, namely, the open position, where it releases the closing element. As the catch moves into this open position, the spring-loaded latch is moved into a stand-by position, in which it rests against the open rotary catch. The latch is thus ready to move back into its locking position or pre-catch position with respect to the rotary catch when the rotary catch is rotated back into its closed position or into a previous pre-catch position. A motor and an energy storage mechanism are used to move the latch from one position to the other. Provided that the user has been granted access, the motor starts to operate as soon as the handle belonging to the rotary catch lock is operated.
2. Description of the Related Art
In the known rotary catch lock (DE 4,221,671 A1), the motor serves only to move the latch from its locking position, in which it holds the rotary catch, to a release position, in which it releases the rotary catch, whereas an energy storage mechanism, which serves as a restoring spring to return the driver which serves to move the latch, is used to move the latch into a stand-by position in preparation for the future locking position. In the known lock, the energy storage mechanism discharges its energy while the rotary catch is in its release position and thus moves the driver back into a starting position corresponding to the locking position of the rotary catch, whereas the latch initially remains in its stand-by position with respect to the rotary catch, which is still in the open position.
The disadvantage of the known rotary catch lock is the relatively large amount of power required to operate the motor. The motor must consume energy not only to shift the positions of the latch and the associated working elements, i.e., to move them from the locking position to the release position, but also to load the energy storage mechanism, so that, after the motor has been turned off, the mechanism has enough energy to move the driver that controls the latch back into its starting position. When the known rotary catch lock is used in a motor vehicle and the vehicle is involved in a crash, the various components of the lock are deformed, and thus more energy is required to move the latch from the locking position to the release position; if the motor is not powerful enough, it will be unable to operate the rotary catch lock, and the occupants will be trapped in the vehicle. The known rotary catch locks require powerful motors, which are not only expensive but also very bulky. This is a problem because of the limited amount of room available in the area of a rotary catch lock.
The invention is based on the task of developing a reliable rotary catch lock of the aforementioned general type which can be operated by a low-power motor and which remains functional even after a crash. This is achieved according to the invention in that the energy storage mechanism acts on a pivoting lever (storage lever), which transfers the stored energy to the latch in order to pivot it into its release position, this energy transmission occurring at least during the final phase of the pivoting motion of the latch under the action of the energy being unloaded from the energy storage mechanism; whereas, while the latch is in the stand-by position and during the initial phase of the pivoting motion of the storage lever, the storage lever rests against a tappet, which is driven rotationally by the motor; and in that the motor can be driven by electronic control logic in either direction of rotation to either of two end positions; that is, either in the forward direction to allow the energy stored in the energy storage mechanism to be unloaded, during which the tappet follows or supports the pivoting motion of the latch under the action of the storage lever, or in reverse to reload the energy storage mechanism, during which the tappet releases the latch, moves toward the storage lever, and moves it into a starting position corresponding to the stand-by position of the latch.
First, the invention shifts the loading of the energy storage mechanism by the motor into a time phase different from the reversing movement by which the latch leaves its blocking position and returns to its release position with respect to the rotary catch. The latch is returned while the motor is operating in the forward direction, whereas the energy storage mechanism is now loaded while the motor is operating in reverse. The energies required for these two measures are therefore not additive but separate, and this makes it possible to use low-power motors. Such motors are inexpensive and space-saving.
In addition, the energy storage mechanism acts on a special pivoting lever, which, while the energy storage mechanism is being loaded during the reverse operation of the motor, is moved by a tappet into a starting position which corresponds to the stand-by position of the latch. Because the energy storage mechanism is being loaded during this movement, this lever is referred to in brief below as the xe2x80x9cstorage leverxe2x80x9d. While the motor is in forward drive, the tappet normally acts only with a braking action during the initial phase of the pivoting motion of the storage lever, i.e., in the phase before the storage lever strikes an adjusting arm belonging to the latch. In this second phase, the energy being released by the unloading of the energy storage mechanism can be used to help move the latch. In a special case, which can be the result of a crash, for example, the tappet pushes against an adjusting arm provided on the latch and thus helps to shift the latch out of its locking position into its release position. In cases such as this where the components cannot move easily, two different energy sources are therefore available: first, the energy of the loaded energy storage mechanism, which is being released by way of the storage lever, and, second, and energy of the motor operating in the forward direction, which acts directly on the latch by way of the tappet. Thus the energies supplied by the motor in two different phases of its operation can be utilized simultaneously to move the latch.